The invention relates to means of autonomous power supply for electronic systems, and in particular to a method and apparatus to provide power supply for microelectronic charges.
Evolution of microelectronics has presently reached the point whereat for power supply of certain (e.g. CMOS) microelectronic circuits, that execute small volumes of computation, an extremely little amount of electric energy for their power supply is required. Therefore efforts are currently made to provide autonomous electric power supply for such microcircuits, using, for example, small-sized galvanic power sources integrated in their casing.
A drawback of such apparatus is a limited service life of a galvanic source.
In this connection, noteworthy are the attempts to abandon the short-life galvanic power supply sources and utilise small-sized apparatuses transforming energy of the sources of the non-electrical nature into the electric energy so that to obtain a small portion of electric charge that would be sufficient to provide power supply for an electronic system for a brief period.
Known, for example, are a method and apparatus to provide power supply for an electronic system through the use of an induction generator based on a stepping motor (U.S. Pat. No. 5,061,923, cl. H 01 Q 9/00, 1991). In said apparatus, for providing power supply for an electronic system used is a mechanical rotation of rotor of the mentioned motor, which rotation allows to induce at the stator winding output an electric voltage that is sufficient to provide power supply for an electronic system. For a number of apparatuses these mechanical movements is a cumber, and the other drawback are relatively large dimensions and a high cost of such motor that restrict utilisation of power supply sources of such type.
Known also are a method and apparatus for generating current pulses to activate a light-emitting diode (U.S. Pat. No. 4,595,864, cl. H 05 B 37/02, 1986). In said apparatus, an impacting mechanical action effected upon a piezoelectric element produces a current pulse, which pulse by a pulse transformer is converted into a current pulse needed to activate a light-emitting diode. In this apparatus, a pulse transformer, as the single element of the circuit, serves as a matching element necessary to provide the efficient passage of a current pulse from a piezoelectric element with a high output impedance to a light-emitting diode with a low input impedance. However, this known teaching is not intended for storing the electric energy produced by a piezoelectric element and needed to procure the steady power supply for electronic systems.
The method that is the most proximate to the invention is a method of power supply for an electronic system, which method consists in converting a non-electric energy into the electric one and storing the electric charges to provide power supply for an electronic system (application EP No. 0,725,452, cl. H 01 L 41/113, 1996). A power supply apparatus for an electronic system that realises said method comprises an electric charge generator using the piezoelectric conversion of the mechanical energy into the electric energy, and an electric charge storage, the output of which storage is the apparatus"" output.
However, the known method and apparatus are of a little efficiency for providing power supply for electronic systems. The cause is that piezoelectric elements, in contradistinction to galvanic sources or induction generators are not sources of electromotive forces (potentials), but are generators of an electric charge. Besides, the value of a portion of an electric charge produced by a piezoelectric element is determined by one-time external mechanical action, and the electric potential emerging at output of such charge generator is directly proportional to a value of said charge and inversely proportional to the value of generator""s output capacitance. In particular, piezoelectric elements allow to obtain the charges having small values with a very high electric potential of the order of several thousand volts. It is not possible to use such high-voltage source for providing the direct power supply for low-voltage electronic systems, such as, for example, microelectronic circuits. The immediate connection to a piezoelectric element of a buffer load electric capacitance for the purpose to store therein a charge needed for power supply for a low-voltage electronic system is not efficient, for the charge portion repeatedly produced by a piezoelectric element is very small, so that for storing a large charge required is a multiple and, accordingly, prolonged mechanical action to be effected upon a piezoelectric element, i.e. required are numerous mechanical depressions of impacts thereon (and in a mechanism according to application EP No. 0,725,452, cl. H 01 L 41/113, 1996 just these steps are implemented).
The object of the invention is to provide a method and apparatus to provide power supply for electronic systems, allowing to significantly improve efficiency of electric power supply sources implemented on the basis of apparatuses for converting the energy generated by sources of energy of the non-electric nature, into the electric energy.
To this end, in a method for providing power supply for an electronic system, which method consists in conversion of a non-electric energy into the electric one and in storing a required quantity of electric charges for the electronic systems power supply, in accordance with this invention the conversion of a non-electric energy into the electric one is carried out by generation of electric charges having a high electric potential, by conversion of the produced charges energy, which conversion is accompanied with an increase of quantity of electric charges and a reduction of their electric potential, with subsequent storing thereof at output of said power supply source, so that power supply for an electronic system will be provided.
Conversion of a non electric energy, in particular, mechanical energy into the energy of electric charges having a high electric potential can be done using a piezoelectric or triboelectric conversion.
Also of interest is the use of high-energy charged particles, which particles come into being as a result of a radioactive decay of a matter, as the charges having a high electric potential.
An apparatus that embodies such method of power supply for electronic systems, comprising a generator of electric charges which converts energy of the non-electric nature into the electric energy of charges having a high electric potential, and an electric charges storage, according to this invention further comprises a converter of energy of these charges, input of which converter is connected to output of a charge generator, and output of said converter is connected to input of the electric charge storage, output of which storage is the output of the apparatus. The charge energy converter is capable of increasing the quantity of the initial electric charges coming to its input from the charge generator, and of decreasing their electric potential.
The basic possibility to attain the above mentioned technical result can be explained basing on the energy conservation law for the conversion of the electric energy pursuant to this invention, which conversion, ideally, has the following form q*=Uin=Q*Uout, where q and Uin, respectively, are a charge and its potential at input of a charge energy converter, and Q and Uout, respectively, are a charge and its potential at output of said converter. Basing on this condition, it can be assumed that for the purpose to increase (multiply) the number of charges at output of the charge energy converter, i.e. so that Q greater than q condition will be satisfied, it is necessary that the potential at input of said converter Uin will exceed the potential at its output Uout. The Uin greater than Uout condition is easily realisable technically, for the potential of the charges produced by charge generators, such as piezoelectric elements or triboelectric elements, is inversely proportional to the own capacitance or load capacitance and is able to reach several thousand volts, while the potential needed to provide power supply for electronic systems, in particular microelectronic circuits, is only several volts. Efficiency of the charges quantity multiplying process will be determined by efficiency of said converter in respect of the process of transfer of electric energy of the initial charge from input of a converter to its output.
An electric charge storage in said apparatus can be implemented as an electric capacitor.
In one of the versions of embodiment of an apparatus for electronic systems power supply, a charge energy converter is implemented as a step-down transformer, the primary winding of which transformer is connected to output of an electric charge generator, and the secondary winding of which is connected through a rectifier to an electric charge storage. Such converter is efficient when a charge generator produces brief high-energy current pulses.
In another version of embodiment of an apparatus for electronic systems power supply, a charge energy converter is implemented as a semiconductor converter, the input region of which converter, connected to output of an electric charge generator, is defined by a semiconductor structure intended for storing the charges from the electric charge generator and for forming the avalanche break-down process when in the semiconductor structure the threshold voltage is exceeded; and the output region of the semiconductor converter is defined by the region of separation and storing of the secondary charges that are formed as a result of the avalanche break-down, and is connected via a rectifier to the electric charge storage. The semiconductor converter input region can be defined by various structures, for example, by inversely-shifted p-n transition, other types of diode structures, as well as by a transistor, or thyristor structure, that will provide a sharper avalanche process of electric charge multiplying.
A charge energy converter can also be implemented as a plurality of capacitors provided with a switch device for switching capacitors from the series connection needed to store charges from a charge generator to subsequent parallel connection allowing to reduce the charges potential at output of a converter and in this way to use the whole charge stored in each individual capacitor to a more complete extent. In this version, the electric charges"" energy produced by a charge generator is used most efficiently.
An electric charge generator can be implemented as a piezoelectric element, triboelectric element. Also of interest is the use of such actually inexhaustible, in terms of capacity, generator of electric charges with a high electric potential as, for example, a radioactive source of charged particles, which source can be implemented as a capacitor, one of the plates of which capacitor comprises a radioactive matter emitting charged xcex2-particles, the other plate being their collector.
Two latter types of an electric charge generator produce charges at a relatively slow rate, and for this reason it is advisable that a series of the above-discussed charge energy converters would be complemented with a short-pulse driver positioned between the electric charge generator output and input of an electric charge energy converter implemented similarly to a gas-discharge tube, or in the form of a semiconductor threshold element, for example, a thyristor.